Do you mean good places in Japan to buy sneakers then Mita in Ueno is pretty good.
http://www.mita-sneakers.co.jp/
and Atmos in Shibuya
ATMOS - TOKYO
Both stock limited editions and collaborations etc
Besides that there is a chain called ABC Mart, they are everywhere in Japan and have quite a good range and usually have some decent sale items.
If it's Japanese designer sneakers you are after then Diet Butcher Slim Skin's flagship store metal burger will have this season's sneaker range if it isnt sold out already
DIET BUTCHER SLIM SKIN